F&O Margin Calculator
Estimate the approximate margin required for index and stock futures & options trades, or the premium required to buy an option — instantly, with no signup.
This is an ESTIMATE only, not your broker's actual required margin. Actual margin is set by the exchange's SPAN system, updates multiple times daily, and varies by broker. Confirm the exact margin with your broker before placing any trade. Insufficient margin can result in a margin call or forced position square-off.
Estimated required margin
₹1,87,200
Approx. 12% of notional value — rounded, not exact.
Notional contract value
₹15,60,000
For context — lot size × lots × price.
Premium received (credited, not netted against margin)
₹15,60,000
This is an ESTIMATE only, not your broker's actual required margin. Actual margin is set by the exchange's SPAN system, updates multiple times daily, and varies by broker. Confirm the exact margin with your broker before placing any trade. Insufficient margin can result in a margin call or forced position square-off.
All calculations run entirely in your browser — nothing you enter here is sent to a server or stored anywhere.
What SPAN and exposure margin actually are
SPAN margin
SPAN (Standard Portfolio Analysis of Risk) is the system NSE Clearing uses to estimate the worst one-day loss your position could plausibly suffer, at a 99% confidence level, by running the position through 16 stress-test scenarios that vary price and volatility. NSE Clearing republishes the underlying risk-parameter files multiple times every trading day — so real SPAN margin is a moving target, not a number fixed at the start of the day.
Exposure margin
Exposure margin is charged on top of SPAN margin as an additional buffer against moves more extreme than SPAN's scenarios already price in. It's generally set as a percentage of the position's notional value — commonly cited around 3% for index futures/options and a higher percentage (or a volatility-based alternative, whichever is greater) for individual stock futures/options, reflecting the greater idiosyncratic risk of a single stock versus a diversified index.
Why buying and selling options require such different margin
An option buyer's maximum possible loss is capped at the premium paid — once you've paid it, you can't lose more, so no further margin is required. An option writer (seller) takes the other side of that trade: their potential loss isn't capped the same way, so exchanges require them to post SPAN + exposure margin against the underlying's full notional value, typically many multiples of the premium they collected. This is the single biggest reason margin requirements differ so drastically between buying and selling the same option.
Why this calculator is an estimate, not a SPAN calculator
A byte-accurate SPAN margin figure requires NSE's daily risk-parameter files and the actual 16-scenario margining algorithm applied per symbol, per strike, per expiry — infrastructure this calculator doesn't have access to. Instead, this page uses commonly-published approximate combined SPAN + exposure percentages (see the sourcing and confidence notes below) to give a rough, directionally useful estimate. It will not match your broker's exact margin requirement, and shouldn't be relied on as if it does.
Frequently asked questions
Why do I need less margin to buy an option than to sell one?
Buying an option caps your maximum possible loss at the premium you paid — you can never lose more than that, so no additional margin is required beyond the premium itself. Selling (writing) an option carries theoretically unlimited loss potential (for calls) or very large loss potential (for puts), since the writer is on the hook for whatever the option is worth at expiry. To cover that risk, exchanges require option writers to post SPAN + exposure margin calculated on the underlying's notional value — usually many times larger than the premium the writer receives.
What happens if my margin falls short?
If your account's margin balance falls below what's required for your open positions — because the market moved against you, or because margin requirements themselves increased — your broker will typically issue a margin call asking you to add funds. If you don't respond in time, or if the shortfall is severe, your broker can forcibly square off (close) your position, potentially locking in a loss at an unfavorable price, and you may still owe additional charges. This is why brokers strongly recommend maintaining a buffer above the exact minimum margin.
Do margin requirements change during the day?
Yes — NSE Clearing publishes updated SPAN risk-parameter files multiple times during the trading day, and required margin moves with them as volatility, the underlying price, and time-to-expiry change. A position that met its margin requirement at 9:20am can require materially more margin by 2pm on a volatile day. The estimate on this page reflects one point-in-time approximation, not a number that holds steady for your whole trading session.
Are the margin percentages on this page exact?
No, and this page is explicit about that: these are commonly-published approximate percentages intended for rough estimation, not NSE's actual SPAN output. Real margin depends on the specific symbol, strike, expiry, and same-day volatility — for individual stocks in particular, real margin percentages can range from under 10% to well over 50%, far wider than a single approximate figure can capture. Always confirm the exact margin with your broker before placing a trade.
What is SPAN margin?
SPAN (Standard Portfolio Analysis of Risk) is the margining system NSE Clearing uses to estimate the worst-case one-day loss on a position at a 99% confidence level, based on scenarios that stress-test price and volatility moves. It's recalculated multiple times a day from live risk-parameter files, which is why the exact figure isn't something a static calculator can reproduce precisely.
What is exposure margin, and how is it different from SPAN?
Exposure margin is an additional buffer charged on top of SPAN margin, meant to cover extreme moves beyond what SPAN's scenarios already capture. It's generally a smaller, more fixed percentage than SPAN (commonly cited around 3% of notional value for index derivatives and a higher percentage for individual stocks), whereas SPAN margin itself moves more with day-to-day volatility.
Your margin also depends on your broker
Margin policies, MTF/leverage products, and how brokers handle intraday vs carry-forward F&O positions all vary by broker on top of the exchange-set SPAN and exposure margin. See each broker's own charges — including brokerage on F&O trades — before choosing where to trade:
Working out an options trade's profit/loss instead of its margin? Use the Options Profit Calculator for P&L, breakeven, and a payoff chart. Trading multiple legs? Try the Option Strategy Builder.
Or use the Brokerage Calculator to compare brokerage and other charges across all brokers side by side.
Learn more: How to Calculate F&O Margin — SPAN, exposure margin & netting explained.
Margin percentages and index lot sizes last verified: 22 July 2026. NSE revises index lot sizes periodically and real SPAN margin changes multiple times a day — treat the figures on this page as a rough, dated approximation, not a live feed.